<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>display</title>
    <style>
        div{
            width: 200px;
            height: 200px;
        }
        .a{
            background-color: rgb(8, 7, 7);
            display: none;
        }
        .b{
            background-color: green;
        }
    </style>
</head>
<body>
    <!-- display: none;隐藏并不再占有原来位置 -->
    display只改变显示模式而不改变元素形式，即行内块不会因此变成块级元素
    <div class="a"></div>
    <div class="b"></div>
</body>
</html>